U.S. Democratic presidential candidate Hillary Clinton said that Islamic State (IS) violence against Iraqi Yazidis and other religious minorities in the Middle East is genocide.

"I was asked this a couple months ago, and I said that term carries with it legal import, it is a very important concept and label for behavior that deserves that name," Clinton said at a town hall in New Hampshire.

"I am now sure we have enough evidence, what is happening is genocide deliberately aimed at destroying lives and wiping out the existence of Christians and other religious minorities," she said.

IS has targeted and killed members of the Yazidi religion, one of the oldest in Iraq, along with Christians and other religious minorities in the regions it controls in Iraq and Syria.

The Obama administration is weighing whether to designate the IS killings as genocide.